The present invention relates to dynamic modeling of the pulmonary trunk using medical images, and more particularly, to modeling and quantitative evaluation of the pulmonary trunk using 4D computed tomography (CT) and magnetic resonance imaging (MRI) data.
Valvular heart disease (VHD) is a cardiac disorder that affects a large number of patients and often requires elaborate diagnostic procedures, intervention, and long-term management. Although left-side (e.g., aortic) valves are affected more often, pulmonary valve diseases also represent a serious health problem. In most case, pulmonary abnormalities occur in conjunction with other heart disease and can be caused by congenital defects, pulmonary hypertension, endocarditis, rheumatic fever, and carcinoid heart disease. Such conditions require constant monitoring and, at some stage, typically require valve intervention. Accordingly, the management of patients with pulmonary heart disease is an important task.
An example of a complex congenital cardiac defect affecting the pulmonary valve is Tetralogy of Fallot (ToF). ToF represents 5-7% of all congenital heart diseases. FIG. 1 illustrates ToF. As illustrated in FIG. 1, ToF includes four defects within the heart structures: ventricular septal defect, narrowing of the pulmonary outflow tract (pulmonic stenosis), an aorta that grows from both ventricles (overriding aorta), and a thickened muscular wall of the right ventricle (right ventricular hypertrophy). In order to manage a patient with ToF, initial surgery to correct the hemodynamic deficiency is usually performed. This surgery involves both widening of the pulmonary tract and closing the ventricular defect. This initial intervention can damage or in some cases destroy the pulmonary valve leading to pulmonary insufficiency. Pulmonary insufficiency causes regurgitation of the oxygenated blood back into the right ventricle (RV) and right ventricle volume overloading. Re-intervention typically includes replacement of the pulmonary valve using a prosthetic valve. The timing for this re-intervention procedure is not well defined and requires constant monitoring of the patient.
Recently, transcatheter percutaneous pulmonary valve implantation (PPVI) has been proposed for inserting the pulmonary valve replacement without the need for surgery. However, the main difficulty of PPVI is that it is difficult to assess the pulmonary trunk before treatment. Due to this difficulty, management of patients with pulmonary valve disease has remained challenging. Valve evaluation and elaborate intervention planning require accurate measurements of pulmonary trunk dynamics and morphology. Magnetic resonance imaging (MRI) or computed tomography (CT) imaging is the modality of choice when high spatial resolution, soft tissue contrast or dynamics is essential. A key advantage to these modalities is the ability to perform multiple non-harmful and accurate scans required for monitoring. Conventional clinical practice involves manually extracting measurements from two-dimensional MRI/CT images in end-diastolic and end-systolic cardiac phases. This is inefficient and in many cases is not sufficiently accurate due to the complexity of the pulmonary trunk anatomy. Manually determining the same relative axial position within the pulmonary trunk can often lead to biased measurements. Furthermore, two dimensional projections cannot capture through plane motion. Changes in axial measurements may be ambiguous as they are caused both by through plane motion and vascular contraction. Moreover, elaborate functional quantifications are not possible using conventional methods.